Watsonia hysterantha

Watsonia
hysterantha is one of numerous, bright, dwarf watsonias endemic
to Western Cape. While several tall-growing watsonias are frequently
used in roadside plantings in South Africa, the potential of dwarf
species as rock garden subjects has yet to be fully appreciated
by a wider audience.

DescriptionW. hysterantha is a most striking scarlet-flowered, autumn-
and early winter-blooming species up to 600 mm high with narrow,
erect, leathery leaves. It is one of the larger dwarf watsonias
and is unique within the genus in being the only member that produces
its flowers before the leaves have fully developed. Its storage
organ is a subterranean corm, covered with several layers of tough
outer tunicsis and it is a strictly winter-growing plant, sending
up its flower spikes just before, or directly after the first autumn
rains, followed shortly afterwards by the leaves that persist until
late spring and die off in early summer. Towards the end of spring,
the large, attractive seed capsules split open, allowing the light,
winged seeds to be effectively dispersed by wind.

Derivation of name and historical facts
The genus Watsonia commemorates the eighteenth century English
physician Sir William Watson. The specific epithet hysterantha
is derived from the Greek hyster, meaning after, and anthos, the
flower, and aptly refers to the appearance of the leaves after flowering
has taken place. W. hysterantha is a relatively recent discovery,
collected for the first time in the 1920s by Mr J.W. Mathews, first
Curator of Kirstenbosch Botanical Garden, who found specimens near
Langebaan. It was formally described in 1927 by Mathews and Dr Louisa
Bolus, a former Curator of the Bolus Herbarium at the University
of Cape Town.

Watsonia comprises 51 species and is endemic to three southern
African countries, South Africa, Lesotho and Swaziland, with the
greatest diversity in the southwestern Cape.

Distribution
and habitatW. hysterantha has a very limited distribution along the
Cape west coast where its corms are confined to deep cracks of granite
outcrops that provide effective protection from ravenous moles and
porcupines, often forming very thick clumps. Its conservation status
is currently categorized as Rare and in certain parts, its habitat
has been destroyed or severely degraded due to the development of
holiday homes. Fortunately though, a portion of its range falls
within the boundaries of the West Coast National Park, as well as
in a couple of private nature reserves near Darling.

Ecology/Pollination biology
Like several other scarlet-flowered Watsonia species with
long, narrow perianth tubes, W. hysterantha is probably pollinated
by sunbirds that feed on the plentiful sugary nectar held at the
base of the perianth tubes, hence the beautifully descriptive Afrikaans
common name suikerkan, that translates literally to sugar
can.

Growing Watsonia hysterantha

W. hysterantha is seldom grown but is admirably suited to
rock garden pockets in temperate climates, where the corms can be
allowed to remain undisturbed for several years. It requires a full
sun position and a sharply drained, preferably acid soil, containing
well-decomposed compost, and needs regular watering during the winter
growing period. The corms multiply prolifically by offset formation
and thick clumps should be lifted every three years to maintain
good flowering performance, as excessively thick clumps seldom produce
flowers. During the summer dormant period the soil must be kept
dry, as the corms soon rot under constantly moist conditions. This
species is thus not suited to general garden cultivation but rather
to a sunny rockery in a corner of the garden reserved for winter-growing
Cape bulbs. Due to its vigorous root system, W. hysterantha
is not ideally suited to containers except if they are very large
(i.e. having a diameter of 35 cm or more).

Thick clumps can be lifted and the offsets separated at any time
during the summer dormant period. They should preferably be replanted
as soon as possible thereafter into dry soil, as corms kept in packets
often fall prey to mealy bug infestation when stored for extended
periods. In addition to offset formation, W. hysterantha
is easily propagated by seeds sown in deep seed trays or seed beds
in autumn, in a well-drained, sandy medium containing some finely
sifted, acid compost. Sow the seeds thinly to prevent overcrowding
and minimize the occurrence of damping-off and rust fungi, and cover
with a 3-5 mm layer of sowing medium (seeds sown too shallow tend
to float to the surface after watering, and fail to germinate).
Water well using a fine rose spray and keep moist. Fresh seeds germinate
within three to four weeks, and at the beginning of the second season,
young corms can be planted out into bags and be grown on for a year
or two. Under ideal conditions, flowers can be expected for the
first time during the third or fourth season.Unlike most other Watsonia
species, the foliage of W. hysterantha is hardly ever subject
to attack by unsightly rust fungi.

To find out if SANBI has seed of this or other SA species, please email our seedroom.
This page forms part of the South African National Biodiversity Institute's plant information website www.plantzafrica.com.